<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>boxSizing的使用 从新定义盒子的大小</title>
		<style type="text/css">
			#d1{
				width: 100px;
				height: 100px;
				background-color: orange;
				padding: 20px;
				border: 3px solid red;
				box-sizing: border-box;
			}
		</style>
	</head>
	<body>
		<div id="d1">
			
		</div>
	</body>
</html>